ATLANTA (Reuters) - A lethal drug that Georgia planned to use on a condemned female inmate was not tainted by another substance as feared when her execution was halted over its cloudy appearance but had been stored at too low a temperature, officials said on Thursday.

Georgia officials halted the March 2 execution of 46-year-old Kelly Renee Gissendaner, on death row for killing her husband in 1997, after officials observed the murky appearance of the pentobarbital solution set to be used in her death by lethal injection.

A state investigation found the drug's appearance changed because it had been stored at a temperature below 59 degrees F (15 C), the Georgia Department of Corrections said in a statement.

The department said testing of the samples confirmed that the drugs had not been adulterated.

It added it planned to correct the mistake, but did not say whether Gissendaner's execution had been rescheduled.

Gissendaner was scheduled to become the first woman executed by Georgia in 70 years.

Her attorneys did not immediately respond to messages seeking comment.

Georgia has also suspended the execution of another condemned inmate, Brian Keith Terrell, while an analysis of the drug supply was conducted.

Terrell, who had been scheduled to die on March 10, was condemned for the 1992 murder of a 70-year-old man.